ApiLoc - A database of published protein sub-cellular localisation in Apicomplexa

version 3 (curated until May 28, 2011)

Organizational changes of the daughter basal complex during the parasite replication of Toxoplasma gondii.

Hu, K. (2008 Jan, PLoS Pathog)

The apicomplexans are a large group of parasitic protozoa, many of which are important human and animal pathogens, including Plasmodium falciparum and Toxoplasma gondii. These parasites cause disease only when they replicate, and their replication is critically dependent on the proper assembly of the parasite cytoskeletons during cell division. In addition to their importance in pathogenesis, the apicomplexan parasite cytoskeletons are spectacular structures. Therefore, understanding the cytoskeletal biogenesis of these parasites is important not only for parasitology but also of general interest to broader cell biology. Previously, we found that the basal end of T. gondii contains a novel cytoskeletal assembly, the basal complex, a cytoskeletal compartment constructed in concert with the daughter cortical cytoskeleton during cell division. This study focuses on key events during the biogenesis of the basal complex using high resolution light microscopy, and reveals that daughter basal complexes are established around the duplicated centrioles independently of the structural integrity of the daughter cortical cytoskeleton, and that they are dynamic "caps" at the growing ends of the daughters. Compartmentation and polarization of the basal complex is first revealed at a late stage of cell division upon the recruitment of an EF-hand containing calcium binding protein, TgCentrin2. This correlates with the constriction of the basal complex, a process that can be artificially induced by increasing cellular calcium concentration. The basal complex is therefore likely to be a new kind of centrin-based contractile apparatus.

PubMed: 18208326, full text

Localisation information

TGME49_110440 (MORN1) phosphatidylinositol-4-phosphate 5-kinase, putative

Experimental localisation: cone shaped body of basal complex during late intracellular tachyzoite, apical during late intracellular tachyzoite, spindle pole during late intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The TgMORN1 compartment is shaped into a cone that forms the main body of the basal complex (Figure 1A-1E), whereas TgCentrin2 is concentrated at the posterior tip of the basal complex (Figure 1D and 1F). Both TgCentrin2 and TgMORN1 are also components of the apical complex. In addition, they are localized to the spindle pole and the centrioles, respectively."
  • Microscopy type: Light
  • Microscopy method: GFP tag, mCherry tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: Cone shaped body of basal complex and apical and spindle pole during mature intracellular tachyzoite

TGME49_050340 (Centrin-2, Centrin2) caltractin, putative

Experimental localisation: cone shaped body of basal complex during late intracellular tachyzoite, apical during late intracellular tachyzoite, centriole during late intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The TgMORN1 compartment is shaped into a cone that forms the main body of the basal complex (Figure 1A-1E), whereas TgCentrin2 is concentrated at the posterior tip of the basal complex (Figure 1D and 1F). Both TgCentrin2 and TgMORN1 are also components of the apical complex. In addition, they are localized to the spindle pole and the centrioles, respectively."
  • Microscopy type: Light
  • Microscopy method: GFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: Cone shaped body of basal complex and apical and centriole during mature intracellular tachyzoite

TGME49_031630 (IMC4) membrane skeletal protein IMC1, putative

Experimental localisation: inner membrane complex
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "(A) A parasitophorous vacuole with parasites at similar stage as those in Figure 3 expressing mCherryFP-TgMORN1 (pseudo-colored green) and EGFP-TgIMC4 (pseudo-colored red). Faint planar concentrations of IMC (red arrows) are surrounded by the TgMORN1 rings (green arrows)."
  • Microscopy type: Light
  • Microscopy method: GFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: inner membrane complex

TGME49_116400 (alpha tubulin, TUBA1) tubulin alpha chain

Experimental localisation: nascent conoid
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The EGFP-TgMORN1 rings (green arrows close to the dotted frames in the TgMORN1 and the merged panels) are formed around the centrioles and possibly nascent conoids highlighted by mCherryFP-TgTubA1 (red arrows at the bottom of the TgTubA1 and the merged panels)."
  • Microscopy type: Light
  • Microscopy method: mCherry tag
  • Strain: RH
  • Gene model mapping comments: annotation matches
  • Localisation record: nascent conoid